Preparing a gun for bluing

byJim Green, GunsmithonMay 28, 2012

Bluing a gun is a chemical process that literally rusts the metal and gives it a blue – black finish that will protect the metal surfaces. A lot of folks often can’t understand why this process can be an expensive proposition at times. It all has to do with proper surface preparation.

Sometimes you can use a buffer wheel on round gun parts such as barrels and magazine tubes. In the above picture, I use a spinning jig to polish out a barrel in partial preparation to blue the gun. But you can’t use a buffer on most guns or gun parts. The reason is, doing so will cause waves on the surface of the metal that are visible after bluing. A buffer also elongates the screw and pin holes on the flats of a receiver. And using a buffer often obliterates the factory lettering on a barrel or receiver too. Nothing ruins the aesthetic looks of a firearm quicker than an amateur polishing job on the metal before bluing a gun. It will be obvious on the finished product.

The majority of proper gun refinishing is all tedious hand labor. In this picture, you see that I have removed the old finish with an acid called blue and rust remover. Then I start the lengthy process of using various grits of wet sandpaper to start polishing the surface to get it ready to drop into the bluing tanks.

I always polish down the length of the barrel and action. Notice the factory lettering is carefully preserved ?

One thing I can never seem to get people to understand is that bluing is a surface finish. What it can NOT do is restore metal that has been pitted. Now it IS possible to fill the tiny metal pits with welding material, but doing so is extremely costly. On an older less valueable firearm, DuraFil and DuraCoat is the best option to fill the pits and hide them.

On this old pump .22 rifle, there’s not much that can be done about the severe pitting. Refinishing an antique gun is often not adviseable as it will ruin the gun for collector’s purposes and hurt the resale value of the gun. But I do get the occasional customer who requests this be done anyway, despite my warnings. Such is the case of this nice old Remington pump .22, a model 12A.

Despite my best efforts, this is about as good as the finish can get.

Sometimes the pitted surfaces end up with a bit of streaking after the bluing tank run. Occasionally the bluing salts can become trapped in the pits. So a trick I like to use is to get an old paper bag from the grocery store. A piece of it is crinkled up and soaked in oil. The paper bag is a very mild abrasive. I can rub it carefully over the streaked surfaces and usually get the color to blend well within reason. However, the pits will remain to be seen in the metal.

Remember — your firearms have only two natural enemies, politicians and rust. While we can always vote one of these enemies away, the other is only gotten rid of by cleaning and careful maintenance of your guns.

To see the process of running the bluing tanks themselves, click on the following link :